Pesticidal methods employing (organosulfonylmethyl) trihydrocarbyltin compounds

ABSTRACT

Disclosed are novel organotin compounds and a process for preparing same. These organotin compounds correspond to the general formula:   where A is alkyl of from 1 to 14 carbon atoms; aryl; substituted aryl; or R2N-, where each R is alkyl of from 1 to 14 carbon atoms; and each R&#39;&#39; is alkyl of from 1 to 14 carbon atoms; or aryl. The organotin compounds of the invention having insecticidal, acaricidal, bacteriostatic, fungicidal and herbicidal properties are employed in the formulation of pesticidal compositions. This is a division of application Ser. No. 164,941, filed July 21, 1971, now U.S. Pat. No. 3,784,580, which in turn is a continuation-in-part of application Ser. No. 10,303, filed Feb. 10, 1970, now abandoned.

=- ited States Patent 1 Peterson 1 PESTICIDAL METHODS EMPLOYING(ORGANOSULFONYLMETHYL) TRIHYDROCARBYLTIN COMPOUNDS [75] Inventor: DonaldJ. Peterson, Springfield Twp., Ohio [73} Assignee: The Procter & GambleCompany, Cincinnati, Ohio [22] Filed: June 8, 1973 [21] Appl. No:368,141

Related US. Application Data 160] Division of Ser. No. 164,941, July 21,1971, Pat. No. 3,784,580, which is a continuation-in-part of Ser. No.10303, Feb. 10. 1970, abandoned.

Peterson 71/97 X [451 July 29,1975

3,782,917 1/1974 Mrowca 71/97 Primary Examiner-James 0. Thomas, Jr.Attorney, Agent, or Firm-Jack D. Schaefer; .lerry J. Yetter; John B.Goodman [57] ABSTRACT Disclosed are novel organotin compounds and aprocess for preparing same. These organotin compounds correspond to thegeneral formula:

where A is alkyl of from 1 to 14 carbon atoms; aryl;

substituted aryl; or R N-, where each R is alkyl of from 1 to 14 carbonatoms; and each R is alkyl of from 1 to 14 carbon atoms; or aryl. Theorganotin compounds of the invention having insecticidal, acari cidal,bacteriostatic, fungicidal and herbicidal properties are employed in theformulation of pesticidal compositions.

7 Claims, No Drawings PESTICIDAL METHODS EMPLOYING(ORGANOSULFONYLMETHYL) TRIHYDROCARBYLTIN COMPOUNDS This is a division ofapplication Ser. No. 164,94], filed July 21, 1971, now US. Pat. No.3,784,580, which in turn is a continuation-in-part of application Ser.No. 10.303. tiled Feb. 10, 1970, now abandoned.

BACKGROUND OF THE INVENTION This invention relates to novel compounds.More particularly, this invention relates to organotin compounds, amethod for their preparation, pesticidal (including herbicidal)compositions containing such compounds and to a method of combatingbothplant and insect pests.

The desirability of controlling or eradicating insect pests and commondisease-causing organisms is clearly accepted. Thus, compoundspossessing insecticidal, acaricidal, bacteriostatic and fungicidalproperties and especially adapted to such control or eradication are ofparticular importance.

The necessity of controlling or eradicating undesirable plants, i.e.,weeds, from fields planted with growing crops by means of chemicalherbicides is also clearly accepted. Such chemical control ofundesirable plant growth is more efficient and less expensive thanmanual control. However, the chemical control of weeds in the presenceof growing food crops has been somewhat hindered because of severalfactors. For example. many herbicides are unsuitable for use with foodcrops because of toxic residues remaining on the crops afterapplication.

It is an object of the present invention to provide novel organotincompounds and a method for their preparation.

A further object is to provide novel compounds which are useful asinsecticides, acaricides, bacteriostats, fungicides and herbicides.Another object is to provide pesticidal (i.e., herbicidal andinsecticidal) compositions containing the novel organotin compounds. Astill further object is to provide novel compositions and methodseffective for combating insects and other pests such as weeds, andbacterial and fungal organisms. Other objects of the invention will beapparent from consideration of the invention described more fullyhereinafter.

DETAILED DESCRIPTION OF THE INVENTION The novel organotin compounds ofthe present invention are of the formula:

where A is a member selected from the group consisting of alkyl of fromI to 14 carbon atoms (e.g., methyl, ethyl, n-propyl, iso-propyl,n-butyl, iso-butyl, amyl, isoamyl, hexyl, n-octyl, ndodecyl,n-tetradecyl); aryl (e.g., phenyl, naphthyl); substituted-aryl (e.g.,pmethoxyphenyl, p-N,Ndimethylaminophenyl, pchlorophenyl,o-methoxyphenyl); and R N-, where each R is alkyl of from I to 14 carbonatoms; and each R is alkyl of from 1 to 14 carbon atoms; or aryl.

In a process aspect, this invention comprises reacting an organometalliccompound having the formula:

wherein M is alkali metal (e.g., lithium); or MgX with atrihydrocarbyltin halide of the formula R 'SnX wherein A, and each R areas defined hereinbefore and X is halide (e.g., chloride, bromide). Thereaction of the organometallic compound and trihydrocarbyltin halideproceeds with facility according to the following scheme:

Suitable organometallic reactants of the process of the inventioninclude the (alkylsulfonylmethyl)lithiums; (arylsulfonylmethyl)lithiums;(substitutedarylsulfonylmethyl)lithiums;(N,N-dialkylaminosulfonylmethyl)lithiums and the corresponding magnesiumhalides. Specific examples include (butylsulfonylmethyl)- lithium;(N,N-dimethylaminosulfonylmethyl)lithium;

(phenylsulfonylmethyl)lithium; (pmethoxyphenylsulfonylmethyl )lithium;(p-N ,N- dimethylaminophenylsulfonylmethyl)lithium;omethoxyphenylsulfonylmethyl )magnesium bromide;

(p-chlorophenylsulfonylmethyl)magnesium bromide.

The process of the present invention is carried out at a temperature offrom about 60C to about 30C, a preferred temperature being from l0C to10C. Especially suitable herein are proportions of reactantscorresponding to about stoichiometric amounts. Examples of suitabletrialkyltin halides and triaryltin halides for reaction with theorganometallic reactants hereinbefore described include trimethyltinchloride, triethyltin chloride, tri-n-propyltin chloride,tri-iso-propyltin chloride, tri-n-butyltin chloride, tri-iso-butyltinchloride, triamyltin chloride, tri-iso-amyltin chloride, tri-nhexyltinchloride, tri-n-octyltin chloride, tri-n-decyltin chloride,tri-n-dodecyltin chloride, trimethyltin bromide, triphenyltin chloride,triphenyltin bromide, and the like.

Tri-n-butyltin chloride is a preferred trialkyltin halide herein andundergoes the desired reaction with facility. Its ready availability andreaction with (phenylsulfonylmethyl)lithium, for example, to provide(phenylsulfonylmethyl)tributyltin having unique insecticidal andacaricidal properties make the tributyltin chloride the trialkyltinhalide reactant of choice.

The process of the present invention can be conducted in the presence ofnon-reactive solvents or diluents. These solvents or diluents should notcontain any of the reactive groups contained in the reactive compoundshereinbefore mentioned either as a part of the structure of the solventor as part of the impurities present in the solvents if maximum yieldsare desired. The use of solvents which will react with organolithiumreactants is also generally undesirable. Suitable nonreactive solventsor diluents are to be found in such classes of compounds as thealiphatic hydrocarbons, aliphatic ethers, cyclic ethers andtrialkylamines. Examples of suitable non-reactive hydrocarbon solventsinclude hexane, petroleum ether and Stoddard solvent. Among the ethercompounds which are suitable as solvents are diethyl ether, dibutylether, tetrahydrofuran, l,2-dimethoxyethane and diethylene glycoldimethyl ether. Amine compounds which can serve as solvents for thereaction include triethylamine and N,N,N,N- tetramethylethylenediamine.Other similar nonreactive solvents or diluents can be used with substantially equivalent results. Preferred herein is tetrahydrofuran whichenables formation of the desired products in high yield and degree ofpurity. The use of mixtures of two or more non-reactive compounds as thereaction medium is suitable.

The organometallic, e.g., organolithium and organomagnesium halidereactants described hereinbefore, can be .readily prepared. Generally,these reactants can be prepared by reaction of a methyl sulfone havingthe formula:

wherein A is as hereinbefore defined with a metalating agent such asalkali metal hydrides (e.g., sodium, potassium and lithium hydride);alkali metal alkyls, wherein the alkyl group contains from i to about 6carbon atoms; alkali metal aryls; and alkylmagnesium halides (e.g.,methylmagnesium chloride). Preferred metalating agents includen-butyllithium and methylmagnesium chloride from the standpoints oftheir facility of reaction and ready availability. Alkylmagnesiumchlorides are preferred for the metalation of substitutedarylmethylsulfones, e.g., p-chlorophenylmethylsulfone, they beingpreferred as tending to minimize side reactions.

The organolithium and organomagnesium halide reactants of the process ofthe invention are prepared by reaction with an appropriate metalatingagent at a temperature of from 60C to about 20C depending on theparticular sulfone, metalating agent, solvent and the like. Reactions ofmethylsulfones with nbutyllithium occur rapidly at room temperaturewhile the corresponding reactions with methylmagnesium halides proceedat moderate to slow rates. Ether and mixed ether-hexane solvents arepreferred, respec tively, when the alkylmagnesium halide andorganolithium metalating agents are employed.

Metalation of sulfones with n-butyllithium, for example, proceedsaccording to the following scheme:

Preparations of organomagnesium halide and organolithium reactants ofthe process of the invention are described in greater detail by LamarField, John R. Holsten and R. Donald Clark, J. Org. Chem., 81,2572-2578, (1959); and by E. J. Corey and Michael Chaykovsky, J. Am.Chem. Soc., 87:6, 1345-1353, March 20, 1965.

The products and processes of the present invention are described inmore detail in the following examples.

EXAMPLE I A 250-ml, three-necked flask fitted with a stirrer, a droppingfunnel, and a thermometer was swept thoroughly with argon and maintainedin an air-free condition by a mercury-filled trap. The flask was chargedwith 27 ml. of tri-n-butyltin chloride dissolved in 50 ml. oftetrahydrofuran (THF). To the solution of tributyltin chloride was addeddropwise with stirring ml. of an approximately one-molar solution of(butylsulfonylmethyl)lithium in a hexane-THF mixture. The temperaturewas held at l0C to 10C during the addition which required l5 minutes.The reaction mixture was then agitated by stirring at room temperaturefor 2 hours. The reaction mixture was hydrolyzed by pouring into aqueousone-molar ammonium chloride. Extraction from the hydrolyzate with ethersolvent and purification by distillation yielded the desired product(butylsulfonylmethyl)tributyltin. The product, a colorless liquid, had aboiling point of l6ll65C/O.l mm. Hg. Analysis gave 48.4 percent Carbonand 9.2% Hydrogen compared to the calculated values, respectively, of48.0% and 9.0%. Infrared and proton nuclear magnetic resonance spectralanalyses confirmed the assigned structure.

Similar results are obtained when the following organotin halides areemployed in an equimolar amount in place of tributyltin chloride in thatthe corresponding (butylsulfonylmethyl)trihydrocarbyltin compounds,respectively, are obtained: trimethyltin chloride; tri-n-octyltinchloride; tri-n-tetradecyltin bromide; triphenyltin bromide.

EXAMPLE ll Employing the apparatus and procedure of Example I, 100 ml.of an approximately one-molar solution of(N,N-dimethylaminosulfomylmethyl)lithium in hexane-THF solvent was addedslowly over a period of 30 minutes to 0.1 mole of tri-n-butyltinchloride dissolved in THF. The temperature at addition was -60C providedby a dry ice-acetone bath and rose through the addition period to 0C.Following the complete addition, the reaction mixture was stirred for 2hours at room temperature (20C) and hydrolyzed by pouring into anaqueous one-molar ammonium chloride solu tion. Extraction from thehydrolyzate with ether solvent and purification by vacuum distillationyielded the desired compound,(N,N-dimethylaminosulfonylmethyl)tributyltin. The product, a pale-yellowliquid, had

a boiling point of from l58-l60C/0.l mm. Hg. Analysis gave 43.8 percentCarbon and 8.5 percent Hydrogen compared to the calculated values,respectively, of 43.7 percent and 8.5 percent. The assigned structurewas infrared by infared and proton nuclear magnetic resonance spectralanalyses.

EXAMPLE lll Using the apparatus and procedure of Example I, 100 ml. ofan approximately one-molar solution of (phenylsulfonylmethyl)lithium inhexane-THE solvent was added dropwise with stirring to 0.1 mole oftributyltin chloride dissolved in THF. The temperature was maintained bymeans of an ice bath in the range of from 0C to 10C. Following thecomplete addition which required one-half hour, the reaction mixture wasstirred for three hours at room temperature and hydrolyzed by pouringinto aqueous one-molar ammonium chloride. Extraction from thehydrolyzate with ether solvent and purification by vacuum distillationyielded an odorless, pale-yellow liquid having a boiling point ofl80C/0.05 mm. Hg. The product, (phenylsulfonylmethyl)tributyltin wasanalyzed and gave 5l.4 percent Carbon and 7.9 percent Hydrogen comparedwith the calculated values, respectively, of 5 l .3 percent and 7.7percent. Infrared and proton nuclear magnetic resonance spectralanalyses confirmed the assigned structure.

The corresponding (phenylsulfonylmethyl)triaryltin compound,(phenylsulfonylmethyl)triphenyltin, is formed when triphenyltin bromideis employed in the above Example in an equimolar amount in place oftributyltin chloride. The compound possesses bacteriostatic activity.

EXAMPLE IV Using the apparatus and procedure of Example I, 100 ml. ofapproximately one-molar solution of(pmethoxyphenylsulfonylmethyl)lithium in hexane-THF solvent was addeddropwise with stirring to 0.1 mole of tributyltin chloride dissolved inTHF. The temperature was maintained by means of an ice bath in the rangeof from 0C to C. Following the complete addition which requiredone-quarter hour, the reaction mixture was stirred for two hours at roomtemperature and hydrolyzed by pouring into aqueous one-molar ammoniumchloride. Extraction from the hydrolyzate with ether solvent andpurification by vacuum distillation yielded an odorless. pale-yellowliquid having a boiling point of l85C/0.05 mm. Hg. The product was(pmethoxyphenylsulfonylmethyl)tributyltin. Infrared and proton nuclearmagnetic resonance spectral analyses confirmed the assigned structure.

EXAMPLE V Using the apparatus and procedure of Example I, 100 ml. of anapproximately one-molar solution of (p-N,N-dimethylaminophenylsulfonylmethyl)lithium in hexane-THF solvent wasadded dropwise with stirring to 0.l mole of tributyltin chloridedissolved in THF. The temperature was maintained by means of an ice bathin the range of from l0C to C. Following the complete addition whichrequired one-quarter hour, the reaction mixture was stirred for twohours at room tem perature and hydrolyzed by pouring into aqueousonemolar ammonium chloride. Extraction from the hydro lyzate with ethersolvent and purification by vacuum distillation yielded an odorless.pale-yellow liquid having a boiling point of l85l90C/0.05 mm. Hg. Theproduct, (p-N,N-dimethylaminophenylsulfonylmethyl)tributyltin wasanalyzed and its assigned structure confirmed by proton nuclear magneticresonance and infrared analyses.

EXAMPLE VI Using the apparatus and procedure of Example I, 80 ml. of anapproximately one-molar solution of(pchlorophenylsulfonylmethyl)magnesium chloride in THF solvent was added(20C) dropwise with stirring to 0.08 mole of tributyltin chloridedissolved in THF. Following the complete addition which requiredonequarter hour, the reaction mixture was stirred for one hour at roomtemperature and hydrolyzed by pouring into aqueous one-molar ammoniumchloride. Extraction from the hydrolyzate with ether solvent andpurification by vacuum distillation yielded an odorless, paleyellowliquid having a boiling point of ll C/0.07 mm. Hg. The product(p-chlorophenylsulfonylmethyl)- tributyltin was analyzed and gave 47.3percent Carbon and 7.0% Hydrogen compared with the calculated values,respectively, of 47.5 percent and 6.9 percent. Infrared and protonnuclear magnetic resonance spectral analyses confirmed the assignedstructure.

EXAMPLE VII Using the apparatus and procedure of Example I, 50 ml. of anapproximately one-molar solution of(omethoxyphenylsulfonylmethyl)magnesium bromide in THF solvent was added(20C) dropwise with stirring to 0.05 mole of tributyltin chloridedissolved in THF. Following the complete addition which requiredonequarter hour, the reaction mixture was stirred for 16 hours at roomtemperature and hydrolyzed by pouring into aqueous one-molar ammoniumchloride. Extraction from the hydrolyzate with ether solvent andpurification by vacuum distillation yielded an odorless, paleyellowliquid having a boiling point of l94-l 95C/0.07 mm. Hg. The product,(o-methoxyphenylsulfonylmethyl)tributyltin was analyzed and gave 50.lpercent Carbon and 7.7 percent Hydrogen compared with the calculatedvalues, respectively, of 50.5 percent and 7.6 percent. Infrared andproton nuclear magnetic resonance spectral analyses confirmed theassigned structure.

Compounds of the invention have been tested as insecticides and asacaricides according to the following methods:

Insecticidal Evaluation Test: Four insect species as follows weresubjected to evaluation tests for insecticidal properties:

I. Adult House Flies II. Southern Armyworm Larvae III. Mexican BeanBeetle Larvae IV. Adult Pea Aphids The compounds of Examples I to IV, VIand VII were dissolved in acetone and dispersed in distilled water withTriton X-IOO (iso-octyl phenyl polyethoxy ethanol) emulsifier. Thesamples were applied for a tensecond period to insects retained in a 2 X5 inch diameter screened cage. The spray was applied from a Watersvertical spray tower operating at l0 p.s.i. and discharging about 30 ml.of material per minute through an atomizer. The spray descends throughan 8 inch stainless steel cylinder to test insects below the atomizer.The insects were retained in the sprayed cages for mortalityobservations. In the case of House Fly treatment, two-hour datarepresent knockdown; 24-hour data refer to mortality. The results areset forth in Table l below.

Table I Insect Mortality Tests Army- Bean Conc. Housc Flies wormsBeetles Aphids Compound (W/VVI) 2 hr. 24 hr. 48 hr. 48 hr. 48 hr.

Example I 0.35 I00 I00 50 100 0.05 l 20( I00) I00 Table l ContinuedInsect Mortality Tests Army- Bean Conc. House Flies worms Beetles AphidsCompound (W/V%) 2 hr. 24 hr. 48 hr. 48 hr. 48 hr.

001 f -(50 100 100) 0.005 25 90 Example 11 0.35 100 100 100 70 100 0.106 65 100 0.05 2 [(100) 100 0.01 100 100 0.005 10 90 7 Example II] 0.35 062 100 90 100 0.1 l00 95 lOO 0.05 90 70 I00 001 40 O 5 Example IV 0.35 00 100 80 100 0.10 95 95 70 0.05 55 45 50 Example VI 0.35 100 100 I00 100lOO 0.10 0 0 95 75 75 0.05 85 30 70 0.0l l5 Example V" 0.35 l0 16 100l00 I00 0.l0 85 0 50 0.05

Numbers in parentheses refer to control composi- Table 2 Continued tionsemployed in a concentration of active equal to that of theweight/percent volume of the compounds of Strawberry Spider Milt?Mortality a 0 the lnventlon. In the case of treatment of House Files, 25Ff" Compound /(W/V (5 da)s) the control compound was 0,0-dlethylO-(2-1sopropyl,4-methyl-6-pyrimidyl)phosphorothioate; the Examplecontrol for the Southern Armyworm and Mexican Bean 100 Beetle larvaetreatments was l-naphthyl-N-methyl- 32%;) carbamate; the control for thePea Aphid treatment 0:001 was S-[ l ,2-bis(ethoxycarbonyl)ethyl]0,0-dimethyl Example 1v 0.35 100 phosphorodithioate. As can be seen fromthe foregoing table, representa- 0.01 c m unds of this invention ossessexcellent in- 0.005 (72 9 p0 p 35 Example v1 0.35 100 sectlcldalpropertles. Particularly notable are the excel- 0'10 100 lent mortalityresults in the case of the treatments of 0.05 100 Southern Armyworm andMexican Bean Beetle larvae and Pea Aphids. Effective knockdown andmortality 0001 22(3) characteristics are also evident from the treatmentof Emmplc 100 40 0.10 100 House Flles wlth compounds of the lnventlon.005 97 Acaricidal Evaluation Testz'The Strawberry Spider 0.01 79(95 Mitewas employed in tests for acaricidal activity. Bean 0005 59(60)seedlings were infested with approximately one hund w 1 r dred mltes'Dlsperslons of test compoun S ere p e As can be seen from the acaricidaldata, the compared by dissolving the toxic material in acetone toprovide a desired weight/volume percent. The solution was then dilutedwith water containing Triton X-100 emulsifier, the amount of water beingsufficient to provide a stable emulsion. The test suspensions weresprayed on the infested bean seedlings. After five days, the plants wereexamined both for post-embryonic forms of the mites as well as eggs. Thepercentage of kill was determined on the basis of the original number ofmites subjected to the treatment with the testsuspensions.

pounds of the invention possess excellent acaricidal properties.Particularly evident are the excellent miticidal properties of apreferred compound, (phenylsulfonylmethyl)tributyltin. The miticidalproperties of this compound compare favorably with those of acommercially available miticide, 4,4'-dichloro-alphatrichloromethylbenzhydrol, employed on an equalconcentration basis. 4,4-dichloro-alpha-trichloromethylbenzhyclrolresults are reported in parentheses in Table 2.

In addition to the excellent acaricidal activity of the compounds of theinvention, the compounds of the invention have a toxicity towarm-blooded animals less than that of some important commercialinsecticides. The oral LD to rats of (phenylsulfonylmethyl)tributyltin,for example, is 400 mg./kg.

To determine the antibacterial activity of the compounds of the presentinvention, the following static test was employed. The speciesStaphylococcus aureus, a gram positive organism used for assayingbacteriostats and found on the skin of both man and lower animals, wasemployed. Compounds of the invention were added to the followingmatrices: FDA nutrient broth; FDA broth plus 25 ppm soap; and FDA brothplus 25 ppm synthetic detergent (commercially available formulationhaving an alkaryl sulfonate detergent active) at levels of IO, 2.5, 0.6and 0.15 ppm. Four contact tubes were used for each dilution tested;three tubes were inoculated and the fourth was held as an uninoculatedcontrol. The FDA nutrient broth consisted of 5 grams Bacto Beef Extract,l grams Bacto Peptone and grams C.P. grade NaCl in 1,000 ml. distilledwater. The inoculum was a 24-hour broth culture of Staphylococcus aureuscontaining about 250 X organisms per ml. and was used in 0. l-ml.quantities. After inoculation, the tubes were shaken thoroughly, allowedto stand for 10 minutes for air bubbles to rise, and read for zero-hourturbidity value using a spectrophotometer at a setting of 610 1.1..After 24 hours of incubation at 37C the tubes were again shaken, allowedto stand 10 minutes, and read for 24-hour turbidity values. Differencesin turbidity values are used as a measure of growth; the higher thevalue the more growth and the less effective is a material. No change inturbidity is evidence for antibacterial activity. The results reportedin Table 3 are extrapolated breakpoints indicating the minimumconcentration of bacteriostat required to inhibit Staph- )[OCOCCZISaureus.

Table 3 Table 5 Test fungus Width of zone of inhibition in mm.

1000 ppm I00 ppm 10 ppm Candida ulbicuns trace 0 0 Tric/mpliymn menla- 3Z trace groplrvtex Glumere/lu riugululu l trace 0 Sclerotr'niufruclit'olu i l 0 Axpergillux niger 4 2 trace ('lmemmimn globosmn StaticTest Against Staphylococcus Aureux Nutrient Broth Matrix ppm S. aureus)Synthetic Deter- As can be seen from the above data, the compounds ofthe invention possess bacteriostatic properties.

The fungicidal activity of the compounds of the present invention wasevaluated as follows:

Compounds of the invention were dissolved in acetone at levels of 1000,I00 and 10 parts per million. One-half inch filter paper discs weresaturated with the test solutions, dried and tested for antifungalactivity by the Agar Plate Test, USDA Circular No. 198, 19317 All testswere performed upon Difco Sabouraud Dextrose Agar. All tests wereincubated at 25C, RH. 96 percent for 5 days. Results for the compound ofExample II are reported in Table 4 as follows: Results in parenthesesrepresent those of a commercially available compound employed on anequal concentration basis, N- trichloromethylthio-4-cyclohexenel,2dicarboximide.

Results of antifungal testing of the compound of Example ll are reportedas follows in Table 5.

The organotin compounds herein are suitable for combating plant pests inthe foregoing manner. In accordance with the present invention, weeds(i.e., postemergent control) or weed seeds (i.e., pre-emergent control)are contacted with an organotin compound of the type described herein inamounts sufficient to achieve the desired degree of weed control. The required dosage depends upon many factors such as method of application,type and quantity of weeds, duration of treatment, climatic conditions,etc. For example, growth suppression or wilting usually requires smallerdosages than does eradication. Application rates of from about 0.25pounds to about 50 pounds of organotin compound per acre are usuallysatisfactory, but higher rates can also be used. Preferably theapplication rate is about 0.5 to 30 pounds per acre.

Any of the organotin compounds of the type herein disclosed are suitablefor use as herbicides. Preferred for this use are those organotincompounds wherein the group A (in the general formula, above) is aryl,especially phenyl, and R N, wherein R is C to C alkyl, and wherein thegroup R is C to C alkyl, especially butyl.(Phenylsulfonylmethyl)tributyltin is especially preferred for use as aherbicide in the manner of this invention.

For practical use as herbicides, the organotin compounds herein areincorporated into herbicidal compositions comprising a plant-compatiblecarrier and an effective, i.e., growth controlling, amount of one ormore of the organotin compounds. (As used herein a plant-compatiblecarrier is defined as an inert solvent or a dry bulking agent of thetype hereinafter disclosed which has no substantial herbicidaleffectiveness but which provides a means whereby the organotin compoundscan be diluted for convenient application.) Such compositions can thenbe applied conveniently to the site of the weed infestation in anydesired quantity. These compositions can be solids, such as dusts,granules or wettable powders, or they can be liquids such as solutions,aerosols, or emulsifiable concentrates. The solid compositions generallycontain from about 1 percent to about 95 percent by weight of theorganotin compounds and the liquid compositions generally contain fromabout 0.5 percent to about 70 percent by weight of said tin compounds.

Herbicidal Evaluation: (Phenylsulfonylmethyl)tributyltin (preparedabove) was screened for herbicidal activity on a variety of plants andplant pests including corn (Zea mays); soybeans (Glycine max), pigweed(Amaranthus retroflexus); wild mustard (Brassica arvensis); barnyardgrass (Echinachloa crusgalli); and hairy crabgrass (Digitariasanguinallis). The test seeds were planted in Market-Pak" containersfilled with about 1500 g. ofa 2:1 mixture (wt.) ofa silty loam top soiland a coarse quartz sand. The (phenylsulfonylmethyl)tributyltin wastested both for pre-emergent and post-emergent efficacy at anapplication rate of 10 pounds per acre (equivalent to ca. 0.037 g. ofmaterial per container, applied in ca. ml. of acetone solvent containing1 percent Tween 20). The solution was sprayed onto the soil surface(pre-emergence) and onto the plant (post-emergence) using an aerosolpropellant power unit. Controls consisted of 3-amino-2,5-dichlorobenzoic acid (Amiben) at 3 pounds per acre as a standardpre-emergence herbicide and 1,1-dimethyl-3-(a,a,a-trifluoro-m-tolyl)urea (Fluormeturon) at 1.5 poundsper acre as the standard postemergence herbicide. The compounds weregraded on a scale of 0 to with 0 being no effect on the plant(post-emergence) or no effect on plant growth (preemergence); 10"represents death (post-emergence) or no growth (pre-emergence). Resultswere as re ported in Table 6.

Table 6 Pig- Wild Barnyard Hairy Plant Corn Weed Mustard Grass Crabgrass Pre-cmergent grade 1 10 10 9 l0 Post-emergent grade 4 l0 l0 101O Amibcn 0 8 9 l0 9 Fluormcturon 1 6 9 7 8 12 and post-emergent, ofpigweed, wild mustard, barnyard grass and hairy crabgrass in thepresence of corn and soybeans is secured. No toxic residues are left onthe crops.

In the above procedure, the (phenylsulfonylmethyl)- tributyltin isapplied broadcase to weedinfested growing alfalfa, oats and tomatoes ata rate of five pounds per acre and chickweed, cockleburr, lambs quartersand foxtail are destroyed without substantial damage to the growingcrops.

The organotin compounds herein are conveniently employed as pesticidesin the form of solutions, em ulsiflable concentrates, wettable powders,dusts, aerosols and the like. Suspensions or dispersions of thecompounds of this invention in a non-solvent, such as water, aresuitably employed in treating plant foliage. Also suitably employed aresolutions of the insecticides, acaricides, herbicides, bacteriocides andfungicides of this invention in oil, and in oil which is emulsified inwater. Examples of oil solvents include hydrocarbons such as benzene,toluene, kerosene and the like, and halogenated hydrocarbons such aschlorobenzene, chloroform, fluorotrichloromethane anddichlorodifluoromethane.

Emulsifiers and wetting agents useful in the compositions herein aresurface active agents of the anionic, nonionic (preferred), cationic,ampholytic and zwitterionic type and normally comprise from about 0.1 to5 percent by weight of the concentrate. Examples of suitable anionicsurface active agents are sodium salts of fatty alcohol sulfates havingfrom 8-18 carbon atoms in the fatty chain and sodium salts alkyl benzenesulfonates, having from 9 to 15 carbon atoms in the alkyl chain.Examples of suitable nonionic surface active agents are the polyethyleneoxide condensates of alkyl phenols, wherein the alkyl chain containsfrom about 6 to 12 carbon atoms and the amount of ethylene oxidecondensed onto each mole of alkyl phenol is from about 5 to 25 moles. Apreferred nonionic herein is the polyethylene oxide condensate ofsorbitan mono-oleate (Tween). Examples of suitable cationic surfaceactive agents are dimethyl dialkyl quaternary ammonium salts wherein thealkyl chains contain from about 8 to 18 carbon atoms and the saltforming anion is a halogen. Examples of suitable ampholytic surfaceactive agents are derivatives of aliphatic secondary or tertiary aminesin which one of the aliphatic substituents contains from about 8 to 18carbon atoms and one contains an anionic water solubilizing groups,e.g., sulfate or sulfo. Specific suitable ampholytic surface activeagents are sodium-3-dodecylaminopropionate and sodium-3- dodecyl aminopropane sulfonate. Examples of suitable zwitterionic surface activeagents are derivatives of aliphatic quaternary ammonium compounds inwhich one of the aliphatic constituents contains from about 8 to 18carbon atoms and one contains an anionic water solubilizing group.Specific examples of zwitterionic surface active agents are3-(N,N-dimethyl-N- hexadecylammonio)propane-l-sulfonate and 3-(N,N-dimethyl-N-hexadecylammonio)-2-hydroxy propanel-sulfonate. Many othersuitable surface active agents are described in Detergents andEmulsifiers 1969 Annual, by John McCutcheon, Inc, which is incorporatedherein by reference.

Aerosols prepared by dissolving the compounds of this invention is ahighly volatile liquid carrier such as trifluorochloromethane,nitromethane, and the like, or

by dissolving such compounds in a less volatile solvent, such asbenzene. and admixing the resulting solution with a highly volatileliquid aerosol carrier, can also be employed to advantage.

The liquid and aerosol compositions herein can contain up to about 70percent (wt.) of the organotin compounds; concentrations of about 1 to lpercent (wt.) are suitable for most purposes.

Compositions in the form of dusts can be prepared by admixing thecompounds of the invention with dry freeflowing powders such as clay,bentonite. fuller's earth, diatomaceous earth, pyrophyllite,attapulgite, calcium carbonate, chalk or the like. Wettable dusts alsoinclude from about 0.1 to 5 percent by weight of one or more of thesurface-active agents described above. The active compounds of theinvention normally comprise up to about 70 percent by weight of suchdust formulations. An amount of up to about 5 percent is preferred andis suitable for most applications.

What is claimed is:

l. A method of combating insects comprising applying thereto aneffective amount of a compound of the formula 0 ll A-s-cm-sn-m' whereinA is alkyl of from 1 to 14 carbon atoms; aryl; substituted aryl; R N-,where each R is alkyl of from 1 to 14 carbon atoms; and each R is alkylof from I to 14 carbon atoms or aryl.

2. A method according to claim I wherein the compound is(phenylsulfonylmethyl trihexyltin.

3. A method according to claim 1 wherein the compound is(phenylsulfonylmethyl) tributyltin.

4. A method according to claim 1 wherein the compound is(butylsulfonylmethyl) tributyltin.

5. A method according to claim 1 wherein the compound is(N,N-dimethylaminosulfonylmethyl) tributyltin.

6. A method according to claim 1 wherein the compound is(N,N-dimethylaminosulfonylmethyl) trihexyltin.

7. A method according to claim I wherein the compound is(butylsulfonylmethyl) trihexyltin.

1. A METHOD OF COMBATING INSECTS COMPRISING APPLYING THERETO ANEFFECTIVE AMOUNT OF A COMPOUND OF THE FORMULA
 2. A method according toclaim 1 wherein the compound is (phenylsulfonylmethyl trihexyltin.
 3. Amethod according to claim 1 wherein the compound is(phenylsulfonylmethyl) tributyltin.
 4. A method according to claim 1wherein the compound is (butylsulfonylmethyl) tributyltin.
 5. A methodaccording to claim 1 wherein the compound is(N,N-dimethylaminosulfonylmethyl) tributyltin.
 6. A method according toclaim 1 wherein the compound is (N,N-dimethylaminosulfonylmethyl)trihexyltin.
 7. A method according to claim 1 wherein the compound is(butylsulfonylmethyl) trihexyltin.